The invention relates to the wind and solar power plants, specifically to such plants which utilize a plurality of rotors, having horizontal axes of rotation, disposed in one building, having means for positioning these rotors towards the direction of the wind and having means for accelerating and guiding the wind towards these rotors. The invention also relates to the power plants utilizing the energy of the sun by converting this energy collected by solar panels into electrical current.
The invented power plant can produce electrical energy at any scale and at a lower cost compared to power plants, that utilize other sources of energy, such as gas, coal, water, or nuclear energy. The invention can work at any site, at any level above or on the ground, by utilizing and accelerating the lowest available wind.
Proposed invention does not pollute the area and does not need as much repairs, maintenance, or expensive protection against terrorist acts or natural disasters, such as earth quake, as compared to nuclear or hydro power plants.
The currently known wind power plants can not win the competition because they do not provide reliable devices, utilizing the advantages and availability of the wind and sun as a source of energy.
Most of the known power systems, utilizing the wind and solar energy, depending on availability of a strong wind, are too small to produce electrical energy on a large scale, use only one generator for transforming the energy of the wind into electrical current, need constant maintenance, and making the cost of the produced energy too high.
For example, in U.S. Pat. No. 4,321,005, Black shows a modular windmill installation, wherein a plurality of individual wind wheels are stacked vertically in a tower-like structure, interconnected with each other and with only one electrical generator, positioned at the base. The design of the vertical shaft and the shields is too complicated and not reliable; the wind wheels are equipped with cups, instead of flat blades and thus can not provide adequate torque because the cups will be constantly filled with the air. This large power plant can produce only a small amount of energy and definitely at a very high cost.
U.S. Pat. No. 4,156,580, inventor Pohl of Canada, shows a system having a number of vertically stacked rotors in combination with a specially adapted tower structure. The tower structure shields the most of the wind energy. The rotors stacked one above another and connected with one vertical shaft, transferring all the collected energy to only one generator; so, the output of energy can not be cost efficient. The weight and related stress do not allow making this shaft too high. Imagine how big the shaft's diameter would be for a ten story high power plant! The rotors initially imply synchronous rotational speed (see FIG. 4), which can cause increasing vibration and can cause breakage of the system.
In U.S. Pat. No. 4,764,683, Coombes describes an invention having two vertical helical rotors, connected with a pair of electrical generators, and a housing, including forward and rear nacelles. Curved blades of the rotors (see FIG. 2) similar to what is shown in FIG. 22 of our invention as known in the prior art, are prone to collect a lot of air between the blades and do not discharge the air after a cycle of rotation, creating friction with the ambient air. The space between the blades is too big, especially for a rotor with two blades, and it takes time for the wind to fill up the space with air, so the impact on one blade will be extended in time, and cause a slow rotation of the rotor. The rotors do not have opposing guiding plates to direct the wind to the blades, as we have in our invention; so, the air of the wind will freely slip outside of the rotor blades, especially for the upper rotor in FIG. 2, having two blades. The sharp, curved and helically pitched blades are too difficult to make and they are not be durable.
In U.S. Pat. No. 4,606,697, Appel shows a pair of vertical rotors, having blades of one rotor projecting between the blades of another rotor. This invention initially implies synchronous rotation of the rotors, which can cause increased vibration and breakage of the system. The blades can stuck to each other as it is shown by phantom lines in FIG. 5, because the zone of low pressure between the adjacent blades of two rotors creates big forces, pressing the blades together. The trailing edges of the blades are difficult to make, they are thin and can be easily broken.
Patent Application Publication U.S. 2003/0122380A1, Harbison, shows a turbine with two vertical rotors, and the frame splitting the wind into two streams, rotating the rotors. The blades of the rotors curved, as it is shown in FIG. 2, similar to FIG. 22 of our invention as known in Prior Art, and will be discussed later. As shown in FIG. 2, the wind can blow from both sides of the axes of rotation of the rotors, diminishing the resulting rotating torque. The pistons 52 can not control the rotational speed of the rotors, because if the back door 45 and 46 will be closed, it will cause to open the side doors, and if we will open the back doors, it will cause to close the side doors. And any change of speed of the wind can cause slumming of the side doors, creating constant noise and turbulence of the wind flow.
U.S. Pat. No. 5,639,208, Theis, employs rotors that are rotated primarily by the frictional forces of a pressured medium flowing through a gap between the rotors. The rotors have substantially smooth surface, and, in one embodiment, have blades shaped as a triangle, but of a very small size, and facing the wind with the smooth, streamlined surface. This solution may be good for a compressor, for a high pressured medium and for a turbine, having a speed exceeding speed of sound. We did not check these conditions but we built a model with triangle shaped blades and tested it at different speeds of wind, blowing by a fan. And, of course, it worked very well, but in opposite to suggested by Theis direction, with the blades, facing the wind in a conventional way, perpendicular to the wind flow, having the front side positioned on the radius from the axis of rotation. The rotors were rotating in this case even with the lowest wind. And best of all the rotors were rotating with horizontal positioning of the axis of rotation, which of course is easy to explain. In this case it is much easier to reach less friction between the rotors and the supportive elements, the rotors are better balanced, and the bearings are loaded symmetrically. As we can see in FIGS. 3, 11, 12, 13, the spaces between the pairs of rotors are not covered as in our invention. It allows the wind to exhaust in these spaces, as it is shown in FIG. B by numerals 44, 69. The wind will lose its speed after the first pair of rotors, and will not have enough power to rotate the second and the third pair of rotors.
U.S. Pat. No. 5,429,480, Van DerVeken of Switzerland, suggested an improved wind engine, comprising a frame, having different stages, separated by decks, and propeller type devices, fixed rotatable inside the frame between supportive pillars. Such big propellers usually are installed separately, on an individual tower, with additional braces to enforce the heavy engine, rotating around the vertical axis. A conventional propeller, used for production of electrical energy, can have more than 150 feet in diameter. So, the frame for six propellers should be really big, high, and costly. The plant should have means to avoid synchronous rotation of the propellers. The work of one propeller will influence the work of the other propellers. And in general, the productivity of known propeller type rotors can not be compared with other engines, using other sources of energy.
U.S. Pat. No. 6,249,059B1, Hosoda of Japan shows a wind power device comprising a wind guide and a twisted member in the wind guide. The wind, coming into the wind guide, is guided around the twisted member and rotates a propeller. A long, twisted way for the wind flow will create large frictional forces between the wind guide and the narrowing surfaces of the twisted member and limit the power of the wind. This invention has a wide open inlet for the wind and a narrow throat of venturi, but do not provide a gradually increasing outlet for the wind. Sudden exhaust of the out-going air from the back side of the device will create turbulence, blocking the exit.
U.S. Pat. No. 4,258,271, Chappel et al, discloses a method and an apparatus for increasing the power output of an impeller, which is mounted in a stream of free flowing fluid, such as water or air. The fluid leaves the impeller at an angle not less than 35 degrees but less than 75 degrees. FIG. 4 of this patent shows approximately similar picture of our invention, although FIG. 5 of the same embodiment illustrates, that the inlet and outlet are shifted in different planes. The type of blades of this patent already was discussed in previous remarks.
U.S. Patent Application Publication No. 2003/0178856A1, Ohya et al, Japan, shows a wind power generator with a propeller rotating in a wind tunnel, accelerating a wind flow. The wind tunnel is having a cylindrical shape and expanding from an inlet to an outlet. The publication provides a number of diagrams showing, that the most efficient angle of inclination of the wind tunnel is in a range from 5 degrees to 25 degrees. These angles are completely different from what is claimed in previous patent by Chappel, and we agree that the data, provided by Japanese inventors in their diagrams, should be more accurate. But it is also clear even without any experimental work, that a smooth inclination provides a smooth air flow, and a sharp inclination, on the opposite, provided a turbulent one. So, in our invention, we tried to keep the angles of inclination of the guiding plates at the smallest possible level. At the same time, too small angles of inclination of the guiding plates create bigger size of the shroud, causing increase in all of the dimensions of the plant and an increase in the cost of the plant.
U.S. Pat. No. 6,710,468 B1 of Mar. 23, 2004, O'Shanahan describes an Elian tower, which is similar to venturi with a rotor, placed in the narrow elongated throat of venturi. Like already mentioned inventions, using a venturi for accelerating the wind flow, this invention also uses a propeller type rotor, rotating perpendicular to the direction of the wind, which creates forces, pushing the rotor in direction of the wind, creating large frictional forces in the bearings along the axis of rotation and losing the energy of the wind. And up to 40 percent of the energy will be lost accordingly to the Betz limits to stimulator 35, situated at the mouth 23 of the conduit 22. O'Shanahan claims that the accelerated wind flow will have a direction perpendicular to the sweeping planes of the rotor (30, 52) (pages 5, 30), but he does not show actually how he can do it. The blades of the propeller should be turned at an angle toward the direction of the wind in order to move across the direction of the wind. On page 3 (65), O'Shanahan writes that a conduit 22 with an intake mouth (23) of 8 meters diameter and a rotor with a sweeping area of 6 meter diameter will have 350 kW of power, but the actual ratio 8 to 6, equal to 4:3, which is shown in FIG. 4 does not give such increase in the speed of the wind and not adequate to receive such power. The conduit 22 has a first area 43, 60 of inlet with a constant cross section and an area of outlet 47, 64, with a constant cross section, which makes the conduit 22 too long, and, since it needs to be rotating towards the direction of the wind around the vertical axis, the occupied area in horizontal plane will be accordingly increased. And the conduit should be made much longer because the angles of inclination of the conical surfaces for the body 55, as it shown for example, in FIGS. 5, 7, are too big and creating too much turbulence in the area of entrance with a possibility to completely block the entrance.
In U.S. Pat. No. 5,836,738, Finney describes an advanced super-venturi power source, comprising a series of at least three venturi tubes having an outlet of one tube positioned in the throat of the second tube, and the outlet of the second venturi tube in the throat of the third venturi. Finney also positioned one turbine in the throats of each one of the tubes, except from the fourth turbine, used as an accelerator for the wind flow from the first three venturi. The system looks very big and bulky, and it will become much bigger if we will include all the structures needed to hold the tubes one inside another and to turn the structure towards the wind. But, despite the fact that the system is relatively big, the output of the energy will be limited. A large generator and a gear box inside of the relatively small throat of the first tube will block the fastest wind streams. Each of the second and the third rotors is having only two blades and most of the wind will slip between the blades, carrying out most of the energy, accelerated by the system. The low efficiency of the chosen rotors, especially for the second and for the third stage is actually acknowledged by Finney in FIG. 1E and on page 27. The rotors of the second and the third stages combined have too small power compared with the rotor of the first stage. The relatively long blades as well as supportive structures, not shown in the drawing, but needed to support the rotors and generators, will cause a turbulent wind flow and an additional loss in efficiency. Despite that the system is relatively big, the output of the energy still will be limited.
In U.S. Pat. No. 4,320,304, Karlson et al, of Sweden, describes an apparatus for increasing the flow speed of a medium, comprising a series of concentric, symmetrically arranged annular members separated by annular slots. These slots can be used to decrease the loss of energy in venturi entrances and diffuser due to the turbulence caused by the restriction of the air by the conical surfaces of venturi. We decided that this patent can provide useful ideas for decreasing the turbulence of air, although our invention has only vertical contraction of the flowing air unlike the frusto-conical contraction of venturi. We provided in our invention new means for decreasing the turbulent flow of wind, and these means are easy to implement. These new means do not produce additional eddies because the restricting surfaces of our invention positioned in flat planes unlike the cited patent, having curved surfaces around the slots which will create additional turbulences. In FIG. 8, Karlson shows a diagram containing data obtained in experiments with the accelerator of FIG. 5. The data shows that at wind speed of 6 m/s, the power output from the turbine is less than 5×10−3 watts. With an accelerator the power was 7 times bigger, reaching 35×10−3 watts and with an accelerator and 4 mms water column pressure drop in the exit area, the power was more than 70×10−3 watts, increasing the power more than 11 times. Karlson did not show how he achieved the drop of the pressure in the exit area, but in our invention we provided a very simple super-diffuser and a booster allowing achieving much bigger drop of air pressure, and at the same time, not increasing too much the dimensions of the device.
Foreign Patent 2,450,362, France, shows a propeller, mounted in a throat of a venturi type tube, having an entrance much bigger than an exit. This patent is similar to the already discussed U.S. Pat. No. 6,249,059, and has similar disadvantages common to patents having propellers mounted in venturi type tube.
Another foreign Patent 2,474,604, France, illustrates similar implementation of propellers, situated in a throat of venturi type tube. All these cited patents as well as many other, using accelerating means and propellers, utilizing the advantages of these accelerating means, have axes of rotation of the propellers positioned in direction of the wind and the blades rotating perpendicular to the direction of the wind, what creates an asymmetrical loading on the bearings and an additional force, pushing the axes of rotation in the direction of the wind, additional friction and a loss of energy to this friction. Most of the energy is slipping between and off the narrow twisted blades of the propellers. All the patents, utilizing the venturi as a means for accelerating the wind, constricting the wind from every direction into a frusto-conical surface, creating eddies and turbulence in every direction perpendicular to this surface, blocking the entrance to the throat of the venturi, especially if the angle of inclination is bigger than 30 degrees, as it is shown in the drawings of these patents. Most of the venturi of the patents has an equal area of exits and entrances, which do not provide suction into the throat of venturi.
In U.S. Pat. No. 6,538,340, Elder implements accelerating means, using narrow stator blades and claiming a new type of rotor, as specifically adapted for a high rotational speed. But, if we take a look at FIG. 1A of the patent, we can see, that large areas of the rotor blades from both sides of the central shaft are not covered from the wind and the stator blades creating only “tower shadowing” along the height of the rotating blades. So if the wind is blowing, for example, in the direction, shown by the reference lines to numerals 11, 12, 10a, to both sides of the central shaft, it will create one rotating torque, turning the rotor in clockwise direction, and another rotating torque, acting in counter-clockwise direction around the central shaft. The resulting torque will be equal to the difference between the two mentioned, and it can be too small to produce adequate energy. Additional resistance to rotate the rotor will come from the “exhaust” zone of the high pressure around the central shaft, creating friction with the blades. The blades, comprising a single, separately standing long plate can not transfer a large rotating torque at a high rotational speed, causing vibration and loss of stability of the rotor. Elder suggests to put his invention on the top of a high rise building. We don't think that people living in this building will approve this idea. The blades of the rotor are mostly not covered and will produce noise, blasts of wind and vibration. Also possible are electro magnetic and radio impulses and interferences which residents of the building will not approve.
U.S. Pat. No. 6,749,393, disclosed by Y. Sosonkina, one of the applicants of this new invention, can help in solving the problem of producing the electrical energy on a large scale by powerful rotors, positioned one above another in one housing, having horizontal axes of rotation, symmetrically loaded from both sides of the rotors and accelerated by an tunnel suction from a wind tail and by contracting the wind at the entrance to the wind tunnel. The only limitation of the previous invention is that it does not have as many means for accelerating the wind as the new invention, capable to increase the speed of the wind and the power of the rotor in hundreds times.
The new invention overcomes this limitation as well as and many others in cited patents. It has small but powerful rotors, capable to perform the work of rotors many times larger in size, avoiding damaging centrifugal forces and related stresses and malfunction. Instead of rotating the large rotors with large circumferential speed of the giant blades, the invention increases the speed of wind by stationary means, which do not demand special maintenance, treatments and replacements. The invention can work at almost any site and capable to work at a wind speed less than 5 miles per hour on the level near the ground. This invention can utilize a rotor train, having only one rotor with two generators, or a rotor train, equipped with six rotors and twelve generators. The rotor trains can be located near the ground or in a high rising building, include one rotor train or a lot of rotor trains, positioned one above another, and collect the electrical power of hundreds of kilowatts.